Clean themes A-L

[hyperupcall]

Description

As per #1696, this cleans up various files by fixing ShellCheck errors.

This cleans 10 themes (and removes two entries from clean_files.txt that no longer exist.

In the agnoster theme, I changed the "Git repository dirty check" to be more consistent with what I added in hawaii50 (to fix a ShellCheck issue).

Motivation and Context

As mentioned in #1696, this minimizes mistakes in the code.

How Has This Been Tested?

Ran ./lint_clean_files.sh successfully.

Screenshots (if appropriate):

Types of changes

• [x] Bug fix (non-breaking change which fixes an issue)
• [ ] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• [x] My code follows the code style of this project.
• [x] If my change requires a change to the documentation, I have updated the documentation accordingly.
• [x] I have read the CONTRIBUTING document.
• [x] If I have added a new file, I also added it to clean_files.txt and formatted it using lint_clean_files.sh.
• [x] I have added tests to cover my changes, and all the new and existing tests pass.